Yieldable thrust-bearing for worm-shafts.



E. P. ASHTON.

YIELDABLE THRUSTBEARlNG FOR WORM SHAFTS.

APPLICATION FILED AUG.3, I912.

5 1 9 1 -11 b 0 Au S d 0U t H m a D1 EDWIN P. ASHTON, 0F DETROIT,MICHIGAN.

YIEIJDABLE THRUST-BEARING FOR WORM-SHAFTS.

Specification of Letters Patent.

Patented Sept. 7, 1915.

Application filed August 3, 1912. Serial No. 713,061.

To all whom it may concern Be it known that I, EDWIN P.'AsHToN, acitizen of the United States of America, residing at Detroit, in thecounty of Wayne and State of Michigan, have invented certain new anduseful Improvements in Yieldable Thrust-Bearings for Worm-Shafts, ofwhich the following is a specification, reference being had therein tothe accompanying drawings.

The invention relates to power transmission mechanism, including arotative shaft which is subjected to end thrust, and more particularlyworm gearing.

It is the object of the invention to provide a simple and thoroughlymechanical construction in which end thrust in one or in oppositedirections is yieldably resisted and further to accomplish this with asingle spring or resilient member.

In the drawings: Figure 1 is a longitudinal section in the plane of theworm shaft showing the latter in elevation; and Fig. 2 is a plan view ofFig. 1.

A is a rotary shaft upon which is mounted the worm B engaging theworm-wheel C, having a transverse a-Xis.

D is a housing inclosing the worm gearing and shaft and including adetachable cap E, separable from the casing in the plane of the shaft.

To take care of the radial thrust the shaft A is provided with journaledportions F and G upon opposite ends of the worm B, and which engagecorresponding ournal bearings H and I formed in the casing D and cap E.These bearingsdo not provide for end thrust and sufficient clearance isleft between the bearing and the worm B to permit a limited endwisemovement of the shaft in either direction.

Adjacent to one end of the bearing such as I is arranged a yieldablethrust bearing of the following construction:

J is a ring on the shaft engaging a shoulder K thereon in the normalposition of parts, and also bearing against a shoulder L on the case,preferably at the end of the hearing I. This ring J forms an abutmentfor the hardened ball-race M of a ball thrust bearing including acoiiperatin race N, a series of balls 0 and a retainer Q is a secondball or roller thrust bearing having similar parts abutting against ashoulder R, upon a journaled bearing S upon the shaft. Between theroller thrust bearingsis a coil spring T sleeved upon the shaft, one endthereof abutting against the race N, while the opposite end bearsagainst a collar U adjacent to the bearing Q. 'This collar has a limitedslidable movement upon the shaft to which it is coupled by a cross pin Vengaging longitudinal slots W, the arrangement being such that the shaftA. has a limited sliding movement in the collar U in the direction ofthe arrow, while movement in the opposite direction will be communicatedto the collar U through the pin V.

In use the shaft A may be freely revolved in the journal bearings H, Iand S to rotate the Worm B and communicate movement to the worm wheel 0in either direction. The end thrust in the shaft resulting from thismovement, if in the direction of the arrow will be yieldably resistedthrough the medium of the shoulder K, collar J, roller thrust bearingsM, N and 0, spring T, collar U, roller thrust bearing Q and shoulder R.Thus any movement will necessitate the compression of the spring T,which is of suiiicient tension to hold the parts in normal position butwhich will yield under any abnormal stress, avoiding stripping of thegears. Where the direction of thrust is opposite to that indicated bythe arrow, the pin V will transmit thrust to the collar U and from thelatter through the spring T to the roller thrust bearings M, N and O,and shoulder L .so that the same spring T yieldably resists thrust inopposite direction To prevent disengagement of the roller bearing Q whenthe collar U is withdrawn therefrom, a coil spring X of comparativelyslight tension is sleeved upon said collar, bearing against a shoulderat one end and at its opposite end against the roller bearing Q. Thisspring is under sufficient tension to take up the motion of the shaftand collar, holding the bearing Q from movement. A tubular casing X'-between the spring X and collar U serves to hold the pin V fromdisengagement.

For taking up any wear which would result in lost motion in thetransmission, the bearing S preferably has a threaded engagement Y withthe casing and is provided with a notched head Y. which is held indifl'erent positions of adjustment by a screw or pin Z. This permits ofadjusting the bearing S longitudinally by disengagement of the pins Zand slightly rotating the notched head Y, after which thepin or screw Zmay be re-inserted to lock the parts from movement.

The bearings H, I and S are preferably provided with detachable caps H,G and S, which may be secured before the engagement of the cap E. Thispermits the assembling of all of the parts of the thrust bearing uponthe shaft A, inserting said shaft in the j ournal bearings, and securingthe caps, after which the space in which the thrustbearing is locatedmay be filled with dope and the cap E then secured in position. The capE in addition to covering the thrust bearing also houses the wormand thejournal'bearings with their independent caps. This construction isadvantageous, and

particularly upon motor trucks and other heavy vehicles where it isdesirable to carry an extra shaft for quick insertion in case ofbreakage. By my construction if a break occurs in the shaft or any partof the mechanism in connection therewith, the caps may be removed, theshaft taken out, and an extra shaft inserted in a very short time.

A further advantage of the construction is that the cap E may be removedto expose all of the mechanism intact when the latter is being tested,as well as during adjustment of the thrust bearing to take up any lostmotion. When the cap E is in place it forms a dust-proof housing inconnection with an end cap E which covers the end of the shaft.

What I claim as my invention is:

1. The combination with a rotative shaft of a collar having a cross pinengagement with said shaft, an anti-friction roller bearing forreceiving thrust from said shaft through the medium of saidcollar, anantifriction roller bearing for receiving thrust in the oppositedirection, a resilient member sleeved. upon said shaft intermediate saidcollar and the last-mentioned anti-friction roller bearing, and aresilient member of lesser tension between said collar and thefirst-mentioned roller bearing.

2. The combination with a rotative shaft of a collar having a cross pinengagement with said shaft, an anti-friction roller bearing forreceiving thrust from said shaft through the medium of said collar, anantifriction roller bearing for receiving thrust in the oppositedirection, a resilient member sleeved upon said shaft intermediate saidcollar and the last-mentioned anti-friction roller bearing, saidcross-pinextending transversely through said shaft and collar andengaging a slotted bearing in the latter, permitting relative movementof the collar and shaft, a tubular casing sleeved about said collar forretaining said pin from disengagement, and a resilient member of slighttension sleeved upon said tubular casing and bearing upon said collarand firstmentioned roller bearing.

3. The combination with a rotative shaft, of a journal bearing therefor,a member arranged on the shaft and disposed to rotate therewith, saidmember being supported for limited movement longitudinally of the shaft,a stop carried by the shaft, a spring embracing the shaft and contactingwith embracing the shaft and contacting with said'member, a thrustbearing interposed between said springand said ring, a memberconstituting a stop embracing the shaft on the opposite side of themember, a spring embracing the member on the shaft, and a thrust bearinginterposed between said stop member and the first mentionedmember andspring.

5. The combination with a rotative shaft, of a journal bearing therefor,a collar on said shaft having a loose connection therewith for limitedmovement in one direction while permitting adjustment in the oppositedirection, a thrust bearing and a-resilient member interposed betweensaid collar and said thrust bearing revoluble with the shaft.

6. The combination with a rotative shaft, of hearings in which saidshaft is journaled, a resilient member sleeved on said shaftintermediate said bearings, anti-friction bearings near'the oppositeends of said resilient member, a collar adjacent one of saidanti-friction bearings, said collar having a connection with the shaftpermitting longitudinal adjustment of the same, and a ring adjacent theopposite "anti-friction bearing having a shouldered engagement with theshaft.

7. The combination with a rotative shaft, of a journal bearing therefor,a collar on said shaft having a loose connection therewith for limitedmovement in one direction while permitting adjustment in the oppositedirection, and a. resilient member sleeved upon said shaft intermediatesaid collar and said journal bearing, saidresilient member beingrevoluble with the shaft.'

8. The combinationwith a rotative shaft,

of a journal bearing therefor, a collar arranged on said shaft, saidcollar being supported fora limited movement longitudinallvof the shaft,a resilient member embracing the shaft and interposed between the collarand the bearing, a stop embracing therewith'for limiting movement in onedirection while permitting adjustment in the 5 opposite direction, and aresilient member sleeved upon said shaft intermediate its c01- lar andsaid journal bearing, said resilient member being revoluble with theshaft.

In testimony whereof I aflix my sigma 20 ture in presence of twowitnesses.

EDWIN P. ASHTON.

Witnesses:

JAMES P. BARRY, DELBERT CoLLINs.

